textproduct: Quad Cities

KEY MESSAGES

- Slowly, the dangerous heat wave will give way to drier air, and more comfortable conditions this evening through Sunday morning.

- The break in the heat will last through Monday night, followed by hot weather Tuesday and Wednesday, with highs reaching the 90s, but with substantially lower humidity values than recent weather.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 256 PM CDT Sat Sep 5 2026

The initial wind shift with the backdoor cool front has already pushed southwest of our CWA, but there is little change in air mass found until you look up near Highway 20 and into Wisconsin. This was largely the expectation leading into today, and is resulting in another excessive heat afternoon for most locations along and south of Highway 30.

CAPE remains plentiful along and south of the boundary, but modest capping much like the past few days is combining with minimal forcing. There has been an eastward progressing outflow boundary across central Iowa late this morning and afternoon, and this will intersect the backdoor front, but that intersection seems to be occurring just west of our CWA border, in the Ottumwa area. A few runs of the HRRR have shown an isolated cell there at times this evening, and I have introduced a narrow 15% pop for Keokuk county this evening. Concerning that, SPC has introduced a Level 1 outlook touching our west edge of Keokuk County. The probability of any storm in our south remains 5-10%, below mention in grid forecasts, but is being mentioned in the graphics for today.

Towards early evening, the increasing northeast wind will bring lower dew point air to the region. This will be a slow transition to drier air, but by morning, some 58-65 degree dew point air should be in place over the CWA, helping it feel far better Sunday and Monday. Skies Sunday do look to have some mid and high clouds, as convection should be found over the west 1/2 of Iowa. This should limit highs to the upper 70s to mid 80s area-wide, and keep heat stress out of the picture through Monday night.

LONG TERM /MONDAY THROUGH FRIDAY/

Issued at 256 PM CDT Sat Sep 5 2026

Dry and seasonally warm conditions will continue through the remainder of the holiday weekend before the upper level ridge begins building back into the area. While LREF probabilities of heat indices greater than 100 degrees are low (10-20%), high temperatures on Tuesday will be around 5-10 degrees above normal. These high temperatures will continue on Wednesday, though there is some uncertainty due to the potential for a front to move through the area Tuesday night into Wednesday morning, bringing in rain and lingering cloud cover that could temper highs on Wednesday.

Wednesday night into Thursday, another boundary will sweep through the area. Much of guidance keeps this boundary dry, owing in part to the frontal passage on Wednesday sweeping out some of the moisture. As northwest flow returns to the region, near-normal temperatures will return through the end of the work week.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1204 PM CDT Sat Sep 5 2026

A backdoor cold front is pushing through our area as of Noon, with winds becoming northeast at all locations except for BRL, which will change over soon. While precipitation is not occurring with the front, there has been quite a bit of stratus and fog today northeast of it, in Wisconsin, northern Illinois, and Minnesota. This has been affecting DBQ most of the morning, and should continue to bring MVFR cigs to DBQ though 20Z before lifting. While models do not offer much cloud cover tonight, the northeast to east flow suggests more stratus could spread back in, and possibly affect all sites. I have added a scattered cig, but this may need to be more directly addressed in the next forecast, as it's common to have back to back cigs behind these backdoor fronts, with cooler, but still moist air from the northeast arriving.

CLIMATE

Issued at 558 AM CDT Thu Sep 3 2026

Record Warm Low Temperatures:

September 5: KDBQ: 76/1881 KMLI: 76/1925

DVN WATCHES/WARNINGS/ADVISORIES

IA...Heat Advisory until 7 PM CDT this evening for IAZ040-051>053- 066. Extreme Heat Warning until 7 PM CDT this evening for IAZ063>065-067-068-076>078-087>089-098-099. IL...Heat Advisory until 7 PM CDT this evening for ILZ009. Extreme Heat Warning until 7 PM CDT this evening for ILZ015>018-024>026-034-035. MO...Extreme Heat Warning until 7 PM CDT this evening for MOZ009- 010.